How DO I Know They Fit?

I can't believe I'm this old, and have to ask a question about buying a pair of boots! Then again, I haven't worm anything but tennies since February. I tried on some ankle boots; 1 size was snug, the 1/2 size larger ws a little loose. Yes, I tried them on later in the day so my feet were 'at their largest'.
For comfort's sake, do I go with the snug fit or the little bit looser fit?

Hmm I would probably go with the larger size and wear thicker socks. Of course, if the smaller ones were only a teensy bit snug, they may loosen up with use...



Well, I'm obviously no help!

Luckily, they're cheap boots; I figure I won't wear them much anyway, so why pay a fortune for them? They're not leather, so I assume there won't be any stretching to them. I'm just so used to tennies I don't really know how the silly things are supposed to feel.